Geophysical surveying is a technique where two- or three-dimensional “pictures” of the state of an underground formation are taken. Geophysical surveying takes place not only on land, but also in marine environments (e.g., ocean, large lakes). Marine geophysical survey systems use a plurality of sensor streamers, which contain one or more sensors, to detect acoustic energy emitted by one or more sources reflected from a hydrocarbon reservoir and/or associated subsurface formations beneath the sea floor. Multiple geophysical surveys taken over time may be referred to as 4D surveying.
An issue encountered in 4D marine geophysical surveying is that variation in temperature, salinity, and/or density of the water as between distinct marine geophysical surveys results in differences in speed of sound in the water and thus differences in arrival times of acoustic signals as between geophysical surveys. The differences in speed of sound may be referred to as “water column static.”